Electrical induction heater for carburetors



May 11,1948. W. N. DICKERSON ET! AL 2, 41,312

ELECTRICAL INDUCTION HEATER FOR CARBURETORS Filed April 5, 1946 PatentedMay 11, 1948 UN I TED.-

ELEcTBIGAL INDUCTION, HEATER FOR AB-' QBS.

WilliamN. Dickerson, Sullivan, 1116., and

Lucas-.D'. Gonzales, El Paso, Tex.

Application Aprilfi, 1946, Serial no. 659,694

1 Claim. 1.

This invention relates to an electrical induction heater for aircraft.carburetors, and more particularly to such a device for use inconjunction with pressureinjcctiontype. aircraft carburetors.

A primary object of this; invention is the provision of a device'adaptedto prevent the forma tion of carburetor ice, andto-remove the same, inthe event that such ice is formed;

An. additional object of the invention is the provisionof such a devicewhichwill minimize engine power loss caused bytheoperatio of theapparatus.

Still a further object of the invention is the provision of such adevice adapted to heat the carburetor in such manner as substantially toeliminate any fire hazards which might be occasioned thereby.

A further object of the invention is the provision of such a devicewhich may be readily applied to any conventional carburetor, and whichwill be effective under a wide variety of conditions and circumstances.

Still another object of the invention is the provision of such a devicewhich will be sturdy and durable in construction, reliable and efficientin operation, and relatively simple and inexpensive to manufacture,assemble, and install.

Other objects reside in the combinations of elements, arrangements ofparts, and features of construction, all as will be more fully pointedout hereinafter and disclosed in the accompanying drawing, wherein thereis shown a preferred embodiment of this inventive concept.

In the drawings:

Figure 1 is a longitudinal sectional view taken substantially throughthe center line of a conventional carburetor for aircraft.

Figure 2 is a top plan view of a portion of the apparatus, certain partsthereof being omitted.

Figure 3 is a top plan view of an additional portion of the apparatus.

Similar reference characters refer to similar parts throughout theseveral views of the drawings.

As conducive to a clearer understanding of this invention, it may herebe pointed out that heretofore methods of preventing carburetor ice havebeen developed, but the conventional anti-ice and de-ice methods areunsatisfactory. In alcohol anti-ice systems, it has frequently beenobserved that so much alcohol is lost by leakage as to render the deviceinoperative, and that such leakage provides a major fire hazard.Further, previously devised air heating systems are ineffective unlessapplied prior to entering an icing. area, and as only a skilledmeteorologist can anticipate all icing conditions, such precaution hasfrequently not been taken. If-an air heating system is appliedafter'iceis indicated by loss. of power, the cylinder heat is seldomsufiicient to remove the ice. 7 r Y Experimentation has disclosed. that.in icing of the carburetor the entire air scoop does not freeze. Thisis-indi'cated by the fact. that the manifold pressure would drop'materially, and this has notwith repeated experiments been indicated. Itfollows-therefore, that since the engine supply of air remains adequate,failure is caused by the lack of fuel. Since the amount of fuel meteredto the engine depends upon the volume of air rushing through thecarburetor, it follows that engine failure is occasioned because theboost venturi and impact tubes are iced over. An important object ofthis invention is, therefore, the provision of a means to preclude theforma tion of ice in the boost venturi and the impact tubes, and thuspreclude failure due to carburetor ice.

Having reference now to the drawings, there is generally indicated at Inan air scoop of an aircraft carburetor, including a main venturi throatI I having positioned therein a plurality of radially positioned impacttubes I2, The tubes l2 communicate with an air chamber 13 positionedbetween the wall of the device and the venturi.

As is customary, the device includes a booster venturi l4 mounted on asuitable supporting bracket l5, and having an exteriorly positionedshoulder IS. A conventional butterfly valve 21 and control rod 28therefor is also provided.

It may here be pointed out that in the customary operation of suchdevice, air enters the boost venturi and simultaneously the impact tubesl2. The difference in pressure between the space l3 into which theimpact tubes I 2 enter, and the pressure in the boost venturi I4controls the movement of the poppet valve which controls in turn theamount of fuel released into the discharge pipe. The structureheretofore described has been conventional, and the instant inventioncomprises the positioning of a coilfof wire I! about the boost venturil4, and an additional coil of wire l8 adjacent the inlet of the impacttubes. In the preferred embodiment of the invention, alternating currentis applied from a conventional aircraft inverter of the 26 volt 400cycle alternating type, to the coils I1 and I8, whereby to heat themetal venturi l l and the booster venturi M in a well known mannerwithout heating the coils l1 and I8 themselves.

The temperatures to which the venturi l I and booster venturi H areheated is dependent upon the number of ampere turns of the coils l8 andI1, and, to some extent, upon the rate at which heat is lost by beingextracted by air passing through the venturis. However, we have foundthat such heat loss is minor, and that a sufilciently high temperaturemay be maintained despite any variations in air temperature or moisturecontent of the air.

Cockpit control for the device may be readily provided by the use of asuitably positioned single throw switch and a warning light wired inparallel in a known manner.

, ing material; of separate high frequency induc- While in the foregoingthe application of the device has been indicated in association with acarburetor of conventional type, it is to be noted that the carburetormay be wired as manufactured and equipp d with a suitable quickdisconnection plug (not shown) for ease of maintenance. Obviously, thecarburetor may be wound in a difierent manner from that herebeforedisclosed in order to accommodate different types of carburetors.

From the foregoing it will now be seen that there is herein provided animproved apparatus, accomplishing all the objects of this invention, andothers, including many advantages of great practical utility andcommercial importance.

As various embodiments may be made of this inventive concept, and asvarious modifications tion coils concentrically disposed about both ofsaid Venturi tubes for rapidly and inductively heating the same and saidimpact tubes to relatively high temperatures to prevent the formation ofice in said Venturi tubes and said impact tubes.

WILLIAM N. DICKERSON.

LUCAS D. GONZALES.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 998,945 Avery et a1. July 25,1911 1,096,989 Bentley May 19, 1914 1,577,276 Whitten Mar. 16, 19261,957,254 Eymann May 1, 1934 2,088,604 Littleiield Aug. 3, 1937

